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Impact modified polystyrene and process for preparing sameRelated Patent Categories: Synthetic Resins Or Natural Rubbers -- Part Of The Class 520 Series, Natural Rubber Compositions Having Nonreactive Materials (dnrm) Other Than: Carbon, Silicon Dioxide, Glass Titanium Dioxide, Water, Hydrocarbon, Halohydrocarbon, Ethylenically Unsaturated Reactant Admixed With A Preformed Reaction Product Derived From: (a) At Least One Polycarboxylic Acid, Ester, Or Anhydride; (b) At Least One Polyhydroxy Compound; And (c) At Least One Fatty Acid Glycerol Ester, Or A Fatty Acid Or Salt Derived From A Naturally Occurring Glyceride, Tall Oil, Or A Tall Oil Fatty Acid, At Least One Solid Polymer Derived From Ethylenic Reactants Only, Mixing Of Solid Graft Or Graft-type Copolymer With Other Solid Polymer Wherein One Of Said Solid Polymers Is Not Derived From Ethylenic Reactants Only; Mixing Of Said Polymer Mixture With A Chemical Treating Agent; Or Mixing Of Graft Or Graft-type Copolymer With A Sicp Or Spfi; Or Processes Of Forming Or Reacting; Or The Resultant Product Of Any Of The Above Operations, Solid Graft Or Graft-type Copolymer Derived From Ethylenic Reactants OnlyImpact modified polystyrene and process for preparing same description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070225440, Impact modified polystyrene and process for preparing same. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation in part of copending U.S. patent application Ser. No. 10/674,224, filed Sep. 29, 2003, which is assigned to the assignee of this application. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to polystyrene. The present invention particularly relates to clear impact modified polystyrene, sometimes referred to as "CLIPS." [0004] 2. Background of the Art [0005] Polystyrene is one of the largest volume thermoplastic resins in commercial production today. Unmodified polystyrene is well suited to applications where its brittleness is acceptable. Engineering plastics have been used in applications where less brittleness is required, but such polymers are often expensive or have properties other than less brittleness that make them less than optimum selections. Thus, styrene-based copolymers, and particularly polystyrene resins that are modified with organic rubber particles, have been investigated for use in applications requiring less brittleness. The modification of polystyrene to reduce brittleness is often referred to increasing its impact properties and thus the modified polystyrene is said to have higher impact. [0006] These high-impact polystyrene blends, commonly referred to by the acronym HIPS, are known to be useful in the art of preparing articles with polymers wherein the application for the articles requires less brittleness than unmodified polystyrene. For example, U. S. Defensive Publication T59,011 to Smith discloses that a high impact resin can be prepared by blending from 15 to 50 parts of an impact modifier with from 85 to 50 parts of a clear crystal polystyrene. Such materials are disclosed to be useful for packaging applications. [0007] Another method of making HIPS is to first dissolve a rubber in styrene monomer and then polymerize the monomer. Such polymers are disclosed in U.S. Pat. No. 6,569,941 Sosa, et al. Therein, it is disclosed that styrene monomer containing a dissolved polybutadiene rubber is flowed into an elongated upflow stirred reactor containing three reaction zones, wherein the styrene monomer is polymerized to form a HIPS. [0008] In addition to modifying styrene with rubber, it has been disclosed to modify styrene using block copolymers. In U.S. Pat. No. 6,362,283, to Wollum, a process is disclosed for interpolymerizing a vinyl aromatic hydrocarbon polymer and a block polymer. The process includes forming a block polymer precursor of at least one polymeric block containing conjugated diene monomer contributed units in the presence of an anionic initiator and in an inert diluent. The block polymer precursor having living ends is adding to a charge of a vinyl aromatic hydrocarbon monomer and an additional charge of an anionic initiator to simultaneously form a block polymer having a terminal block formed from the charge of vinyl aromatic hydrocarbon monomer attached to the block polymer precursor and a poly(vinyl aromatic hydrocarbon) polymer interpolymerized with the block polymer. SUMMARY OF THE INVENTION [0009] In one aspect, the present invention is impact modified polystyrene. The impact modified polystyrene is prepared using a process including dissolving a styrene-butadiene-styrene block copolymer in styrene monomer and polymerizing the styrene monomer wherein the clear impact modified polystyrene has a haze of less than or equal to 12 percent. [0010] In another aspect, the present invention is a process for preparing an impact modified polystyrene. The process includes dissolving a styrene-butadiene-styrene block copolymer in styrene monomer and polymerizing the styrene monomer wherein the impact modified polystyrene has a haze of less than or equal to 12 percent. [0011] Another aspect of the present invention is a composition of an impact modified polystyrene prepared using a process including dissolving a styrene-butadiene-styrene block copolymer in styrene monomer and polymerizing the styrene monomer wherein the impact modified polystyrene has a ratio of Mz/Mn of at least 4.1. [0012] Still another aspect of the present invention is a process for preparing an impact modified polystyrene including dissolving a styrene-butadiene-styrene block copolymer in styrene monomer and polymerizing the styrene monomer wherein the impact modified polystyrene has a has a ratio of Mz/Mn of at least 4.1. [0013] Yet another aspect of the present invention is a composition of an impact modified polystyrene prepared using a process including dissolving a styrene-butadiene-styrene block copolymer in styrene monomer and polymerizing the styrene monomer wherein the impact modified polystyrene has a haze value of less than or equal to 12 percent, the styrene-butadiene-styrene block copolymer is a tapered block copolymer having a styrene content of about 70 percent, a Mw of from about 50,000 to about 250,000 Daltons, and is present at a concentration of from about 5 to abut 20 percent. BRIEF DESCRIPTION OF THE DRAWINGS [0014] For a detailed understanding and better appreciation of the present invention, reference should be made to the following detailed description of the invention and the preferred embodiments, taken in conjunction with the accompanying drawings, wherein: [0015] FIG. 1 is a graph showing the effect of block copolymer concentration on polystyrene formation with and without n-dodecyl mercaptan (NDM), a chain transfer agent; and [0016] FIG. 2 is a graph showing the effect of block copolymer concentration on the molecular weight distribution of polystyrene with and without NDM. DETAILED DESCRIPTION OF INVENTION [0017] In the practice of the method of the present invention of preparing an impact polystyrene, a styrene-butadiene-styrene copolymer is dissolved in a styrene monomer and then the styrene monomer is polymerized. This process is a solution polymerization process and can be performed in any fashion known to be useful to those of ordinary skill in the art of performing such processes. For example, the impact modified polystyrene of the present invention can be prepared using the process disclosed in U.S. Pat. No. 6,569,941 Sosa, et al., which includes using an upflow reactor. In another embodiment, the process of the present invention can be practiced using a single batch reactor. [0018] The present invention includes dissolving a styrene-butadiene-styrene copolymer in styrene. In one embodiment of the present invention, styrene-butadiene-styrene copolymers useful with the process of the present invention are those having the general formula: S--B--S wherein S is styrene and B is butadiene or isoprene. In another embodiment of the present invention, the styrene-butadiene-styrene copolymers have the general formula: (SB).sub.nX. wherein X stands for the residue of a coupling agent; and n is more than 1. In a first embodiment of the present invention wherein such a radial styrene-butadiene-styrene copolymer is used, n is an integer ranging from about 2 to about 40. In another such embodiment, n is an integer ranging from about 2 to 4 or 5. The styrene-butadiene-styrene copolymers useful with the process of the present invention can have a molecular weight ranging from about 2,000 to about 300,000 Daltons. In one embodiment of the present invention, the styrene-butadiene-styrene polymers useful with the present invention have a molecular weight of from about 50,000 to about 250,000 Daltons. In still another embodiment, the styrene-butadiene-styrene polymers useful with the present invention have a molecular weight of from about 75,000 to about 200,000 Daltons. [0019] For purposes of the present invention, the term styrene-butadiene-styrene includes the compositions where the butadiene component is isoprene and also compositions where the butadiene element is a mixture of butadiene or another conjugated diene. While the vast majority of S--B--S copolymers utilize butadiene as the B component, any conjugated diene can be used in the present application and is within the scope of the claims. Continue reading about Impact modified polystyrene and process for preparing same... Full patent description for Impact modified polystyrene and process for preparing same Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Impact modified polystyrene and process for preparing same patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Impact modified polystyrene and process for preparing same or other areas of interest. ### Previous Patent Application: Graft copolymer and resin composition containing the same Next Patent Application: Aqueous resin dispersion for adhesive and composition thereof Industry Class: Synthetic resins or natural rubbers -- part of the class 520 series ### FreshPatents.com Support Thank you for viewing the Impact modified polystyrene and process for preparing same patent info. IP-related news and info Results in 0.16215 seconds Other interesting Feshpatents.com categories: Tyco , Unilever , Warner-lambert , 3m 174 |
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